Regulator



J. F. KOVALSKY ETAL REGULATOR Filed May 5, 1959 June 17, 1941.

22 24 2s .D/lw'ance in Mill/melee INVENTORS Joseph 5 4 0 va/sry and Z a wrenyce 1. Eur) fair).

ATTO N WITNESSES:

Patented June 17, 1941 REGULATOR Joseph F. Kovalsky, Tu Fountain, Wilkinsbu vania 8, inghouse Electric & M East Pittsburgh, Pa., 8.

rtle Creek, and Lawrence L.

Pa., assignors to Westanufacturing Company, corporation of Pennsyl- Application May 5, 1939, Serial No. 271,909

6 Claims.

Our invention relates to regulating apparatus and particularly to regulators of the rheostatic type, such as are desirable for controlling the excitation of dynamo-electric machines, although the invention is not limited to this application.

It is an object of our invention to provide a regulator system employing a regulator of the rheostatic type for controlling the excitation of the dynamo-electric machines that require a small amount of energy to operate and in which the rheostat controlling element is movable through a small range of travel for efi'ecting a large correction of the regulated quantity.

Another object of our invention is the provision 01' a regulator in which means is provided for recalibrating the regulator coil circuit to compensate for large changes in coil current resulting from a characteristic droop in the regulated voltage with change in the position of the resistor controlling arm.

More specifically stated, it is an object of the invention to compensate the regulator to obtain a pull curve of the regulator operating magnet that substantially matches the characteristic curve of the restraining spring and contact load without an appreciable droop in regulated voltage throughout the range of operation of the regulator.

Other objects and advantages of our invention will be apparent from the description of one preferred embodiment of our invention, reference being had to the accompanying drawing, in which:

Figure 1 is a diagrammatic view of apparatus and circuits organized in accordance with the invention;

Fig. 2 is a side elevational view of a regulating relay operating structure employed in the invention, with the contact members operated thereby and their associated resistors shown diagrammatically; and

Fig. 3 illustrates a set oi curves.

Referring particularly to Figure 1 of the drawing, a regulator system is illustrated that is arranged for controlling the voltage of a generator having an armature I connected to supply energy to circuit conductors 2 and 3, and a field winding 4 connected in shunt relation to the armature through a circuit including conductor 5, regulating resistor 6, conductor 1, generator field rheostat 8, field winding 4 and conductor 9. The excitation of the field winding 4 is controlled by a rheostatic device I l which, in addition to the regulating resistor 6, includes a plurality of leaf springs l2 arranged in a stack having their fixed ends insulated from one another and connected by conductors l3 to a plurality of points spaced along the resistor 6. The fixed ends of the leaf springs l2 are insulated from one another by strips of insulating material I4 and are retained between pressure plates l5 and It by a suitable clamping means H. The other ends of the leaf springs l2 are free to move and have a biasing force toward the left, as viewed in Fig. 1, into engagement with a stop block l8 of insulating material for limiting their motion in one direction and for spacing the free ends of the leaf spring elements l2 so that contact buttons l9 carried thereby are out of contacting engagement with the buttons carried by adjacent leaf springs elements when the ends of the leaf springs are in engagement with the stop block l8. The leaf springs l2 are adapted to be moved into circuit closing engagement by a driving member 20 carried on a movin arm 22 for controlling the position of the leaf springs l2 to adjust the effective value of the resistor 6. The movable arm 22 is pivotally mounted at 23 and is subject to movement about the pivot in response to the force of a spring 24, one end of which is connected thereto and the other end of which is connected to an abutment 25 and the opposing force of an armature 26 carried at one end of the lever 22 and actuated by a magnet 21 energized by a winding 28. The winding 28 is connected to a circuit that is energized in accordance with the voltage to be regulated or, in the present application of the invention, from conductors 2 and 3. This circuit extends from conductor 2 through conductor 29, voltage adjusting rheostat 32, winding 28, conductor 33, a resistor 34 of a second rheostatic device 35, conductor 36, the primary winding 31 of a stabilizing transformer 38 to junction point 39 on conductor 3. The primary winding of the transformer 38 is connected to conductors 43 and 44 across the field winding 4.

The rheostatic device is similar in general construction to the rheostatic device I l and comprises, in addition to the resistor 34, a plurality of leaf springs 45 forming a stack separated from one another by strips of insulating material 46 and connected by conductors 41 to spaced points along the resistor 34. The fixed ends of the leaf springs 45, together with the insulating strips 46 are clamped between clamping plates 48 and 49 by clamping means 5|. The free ends of the leaf springs 45 are free to move and have a biasing force toward the right as viewed in Fig. 1 into engagement with a stop block 52 of insulating material for limiting their motion in one direction and for spacing the electrically conducting contact members 53 out of contact engagement with one another except as moved into engagement by a driving member 56 carried on the moving arm 22. Stops 55 and 58 are provided on the arm 22 for limiting the movement of the arm in the one or the other direction.

The leaf spring assembly of each of the rheostatic devices II and 36 may correspond generally to the construction disclosed in greater detail in the copending application of C. R. Hanna et al. Serial No. 203.876, filed April 23, 1938, for regulators and assigned to the same assignee as this application. The two sets of leaf spring assemblies for controlling the effective values of the resistors 6 and 34, respectively, are so arranged that as the arm 22 moves in one direction, say toward the right, it causes successive engagement of the contact members l8 to short circuit successive portions of the resistor 6 while permitting separation of successive contact members 63 to remove the short circuit of successive steps of the resistor 34 upon the engagement of the lower ends of the leaf spring 65 with the stop block 52. Movement of the lever 22 in the opposite direction causes an opposite variation in effective values of the resistors 6 and 34 introducing successive steps of resistor 6 into the generator field winding circuit while short circuiting successive steps of the resistor 34 from the regulator operating winding circuit.

Referring to Fig. 2, the core structure provided is formed in the shape of a square C and comprises a winding leg about which the turns of the energizing winding 28 are wound and to the opposite ends of which inwardly projecting core legs are connected, terminating in faces 61 and 58 that are spaced to provide for the armature 26 of magnetic material therebetween. The armature 26 is fastened by screws 59 to the lower end of the arm 22 and has two opposite parallel faces positioned adjacent the faces 51 and 58 of the core structure to provide a double air gap of substantially constant value independently of the position of the armature 28 within its range of travel. The inner surface 62 of the armature 26, as viewed in Fig. 2, is cut away at its lower portion so that as the armature travels within this air gap, a varying width from the top to the bottom of the armature 28 will be included between the surfaces thereof to provide the desired pull characteristic of the armature.

The movable arm 22, carrying the armature 26 at its lower end and the driving members 20 and 54 at its upper end, is supported by leaf springs 63 and 64 to provide a substantially frictionless pivot 23 along the line of intersection of the planes of the springs 68 and 68, as shown in Fi 2. I

A supporting bracket 65 is shown attached to the core structure 21 by means of screws 68. A second bracket 61 is provided and is attached to the movable arm 22 by screws 68. The upper ends 'of the vertical springs 64 are attached to the bracket 63 by means of screws 12. The outer ends of the horizontal springs 63 are attached to the bracket 65 by means of screws 13 and the inner end of the springs 63 are attached to the bracket 61 by means of screws II. The bracket 25 to which one end of the restraining spring 26 is attached is illustrated as being mounted on the winding leg of the core structure by a screw 15. The magnet structure assembly for operating the lever 22 may correspond substantially to that shown in copending application of Ralph A,

88 is a characteristic load curve of a regulator employing the regulating rheostatic device ll without the compensating rheostatic device 36. This curve includes the loading of the restraining spring 24 plus the loading of the regulating resistor leaf springs l2 indicated in pounds force for varying positions of the movable lever 22 plotted as distance of movement of the driving member l8, over the operating range of the resistor contact members.

Curves 8| to 88 are a family of curves showing the pull of the core 21 on the armature 26 over the same range of movement of the lever 22, each curve representing a particular value of current through the regulator coil 28 such, for example, as from .080 to .120 ampere for a typical magnet structure.

It will be noted that each of the pull curves 8| to 88, corresponding to different specific values of coil current, cut the curve at definite angles insuring stability of the regulator operation at such points.

The range of movement of the driving member 20 shown in Fig. 3 corresponds to the operative range of the rheostatic device H controlling the excitation of the machine being regulated. If the regulator has a load curve corresponding in character to curve 88 in Fig. 3, the regulated voltage will not be automatically held constant over this range, since the current in the regulator coil varies from .120 ampere to .080 ampere as the armature moves from one limit to the other.

In accordance with the present invention, means is provided for changing the coil circuit resistance automatically with the movement of the regulator arm 22. In order to maintain the regulator sensitive to slight changes in voltage at all armature positions, it is necessary to vary the resistance in the coil circuit in such manner that the product of the coil current and the resistance of the coil circuit is substantially constant for all armature positions.

The operation of the regulator here described is as follows: With the several leaf springs l2 in the positions illustrated in Fig. 1, each contact member is in engagement with the adjacent contact member of the stack, thus shorting the entire resistor 6 from the circuit of the field winding 4 of generator I. Likewise, the several leaf springs 45 of the rheostat device 35 are biased toward the right into engagement with the stop block 52 so that the several contact members 53 carried thereby are separated from adjacent contact members thus introducing the entire resistor 34 into the circuit of the winding 28 of the regulator. When the generator is started and the voltage on the output circuit 24 is low, the force of the spring 24 is much greater than the magnetic pull on the armature 26 so that the driving member 20 on the movin arm 22 is biased against the contact button I! in the nearest leaf spring I 2 with sufficient force to raise the ends of the several springs from the surface of the block l8 and brings the contact buttons carried by the several leaf springs into circuit closing engagement. Thus the several portions of the resistor 6 between the several tapped connections l3 are shorted from the field winding circuit. As the voltage of the generator builds up to its desired value, the force on the armature 26 increases causing the arm 22 and the aaeasoa driving members 20 and 54 to move in a counterclockwise direction, the member permitting a number of the springs I2 to engage the block it and the driving member 54 moving to engage the contact member 53 of the nearest leaf spring 45 to cause it to engage the adjacent contact member and to cause continued engagement of a number of adjacent contact members in sequence depending upon the amount of movement of the member 54. At the desired generator voltage value, the pull on the armature 28 just balances the total spring loading of the arm 22 including the pull of spring 24 and the sum of the forces exerted by leaf springs l2 and 45 effecting some intermediate value of the resistor O determined by the number of portions thereof that are short circuited.

As the arm 22 moves in a direction to increase the number of sections of the resistor 6 that are short circuited it decreases the number of sections of'the resistor 34 that are short circuited and when moved in the opposite direction, or toward the left as viewed in Fig. 1, it effects a decrease in the number of sections of the resistor 6 that are short circuited and an increase in the number of sections of the resistor 14 that are short circuited, so as to vary the current through the circuit of the regulator coil 28 with varying armature positions. When the voltage in the regulated circuit is at its normal value after any variation thereof, the magnetic pull on the armature 26 will balance the loading on the lever 22 resulting from the forces exerted by the spring 24 and as many of the leaf springs l2 and 45 as are effective for the particular position of the lever 22.

It will be appreciated that the amount of resistance provided in the several sections of resistor 34 tapped by conductors 41 may be arranged to develop a pull curve that approaches as closely as may be desired the characteristic curve of the restraining spring 24 and the contact load resulting from the leaf springs l2 and 45. It will ordinarily be desired that the characteristic curve of the regulator representing the position of the driving members 54 and 20 with respect to voltage across the regulated circuit conductors 2-3 have a slight droop with decreasing field resistance in order to effect stable operation of the regulator. The desired curve may be developed by introducing the proper resistance values between tapped sections of the recalibrating resistor 34.

Various modifications in the details of the apparatus and circuits illustrated and described will be apparent to those skilled in the art with. in the spirit of my invention and I do not wish to be limited otherwise than by the scope of the appended claims.

We claim as our invention:

1. In a regulator system, electrical apparatus, a circuit connected thereto, means for governing the operation of said electrical apparatus to control an electrical characteristic of said circuit comprising, in combination, two circuit controlling devices each including a resistor, a plurality of elongated circuit controlling members arranged with one end of each supported in fixed relation and connected to separate points along said resistor, said fixed ends being insulated from one another, the other ends of said members being free to move, stop means against which the free ends of the circuit controlling members are biased for limiting the spacing of the free ends,

said stop means being arranged to permit unlimited movement 01 the circuit controlling members away from the stop means, a driving mem-' ber positioned for progressively moving the circult controlling members of one of said circuit controlling devices from engagement with this associated stop while permitting progressive engagement of the circuit controlling members of the other of said circuit controlling devices with their associated stop, a magnet structure including a moving armature for controlling said driving member, means for biasing the armature against the pull of said magnet, and means including an electric circuit for energizing the magnet in accordance with the quantity to be regulated, one of said two above-named circuit controlling devices being included in said circult for adjusting the pull curve of said magnet with varying positions of said armature.

2. In a regulator system, an electric circuit, a means for adjusting a characteristic of said electric circuit comprising, in combination, two automatic rheostatic devices each including a resistor, a plurality of contact members connected to separate points along said resistor, stop means for spacing the contact members relative to adjacent contact members when actuated to the limit of movement permitted by the stop means, the relative movement of said contact members and said stop means being unrestricted in one direction, and control means including a movable element for actuating said two automatic rheostatic devices to vary the effective value of their associated resistors in opposite directions, means for constantly biasing said movable element in one direction, and electroresponsive means including a winding connected to a circuit energized in accordance with the regulated quantity for moving said element against biasing means. one of said rheostatic devices being connected for varying the regulated quantity and the other being connected in circuit with said winding to compensate the energization of the winding for varying positions of the armature.

3. In a voltage regulator for a dynamo-electric machine having a field winding, means responsive to the regulated voltage for governing the excitation of said dynamo-electric machine comprising a rheostatic device having a field regulating resistor, a plurality of contact members connected to separate points along said resistor, stop means for spacing the contact members when engaged thereby, said stop means being arranged to permit unlimited movement of the contact members away from the stop means, means for biasing the contact members to the positions limited by the stop means, electroresponsive means including an armature acting against a biasing force for varying the effective value of said field regulating resistor, an energizing circuit for the electroresponsive means and means for applying a voltage thereto that is a measure of the regulated voltage, and'a recalibrating rheostat similar to said above named rheostat having its resistor connected in circuit with said electroresponsive means and operatively connected to said armature for varying the eil'ective value of said recalibrating resistor in a direction contrary to variations in the eflective value of said field regulating resistor.

4. In a voltage regulator for a dynamo-electric machine having a field winding, means responsive to the regulated voltage for governing the excitation of said dynamo-electric machine compristhe force of said ing a field regulating'rheostat having a resistor, a plurality of contact members connected to separate points along said resistor and biased to spaced positions, a drivingmember ior actuating said contact members into circuit closing engagement with adjacent members to short circuit selected portions of said resistor, a restraining spring for biasing said driving member in one direction, electroresponsive means including an armature for biasing said driving member in the opposite direction, an energizing circuit for the eleqtroresponsive means and means for applying a voltage thereto that is a measure of the regulated voltage, and a recalibrating rheostat similar to said above named rheostat having its resistor connected in circuit with said electroresponsive means and operatively connected to said armature for varying the eflective value of said recalibrating resistor in a direction to compensate for varying load on the armature with change in position thereof.

5. In a voltage regulator for a dynamo-electric machine having a field winding, means responsive to the regulated voltage for governing the excitation of said dynamo-electric machine comprising a rheostatic device having a field regulating resistor, a plurality of contact members connected to separate points along said resistor, means for biasing the contact members to spaced positions, electroresponsive means including an armature for progressively actuating said contact members to short circuit varying portions of said field regulating resistor, a restraining spring for opposing the movement of said armature by said electroresponsive means, an energizing circuit for the electroresponsive means and means for applying a voltage thereto that is a measure of the regulated voltage, and a recallbrating rheostat similar to the above named rheostat having its resistor connected-in circuit with said electroreponsive means and operatively connected to said armature for varying the effective value of said recalibrating resistor in a direction to compensate for varying load on the armature with change inposition throughout its range of operation.

6. In a regulator system for governing the excitation of a dynamo-electric machine for automatically controlling an electrical characteristic thereof, in combination, a regulating resistor, means for varying the effective value of said regulating resistor comprising a plurality of spring biased contact members connected to separate points along said resistor, an electromagnet and an armature actuated thereby, a restraining spring for biasing' said armature against the magnetic pull of the magnet, said contact members and said restraining spring providing a varying load-with-position characteristic in opposition to the magnetic pull on the armature, an energizing circuit for the magnet and means for applying a voltage thereto that is a measure oi. the regulated quantity, and a variable recalibrating resistor in the energizing circuit of said electromagnet controlled in response to the movement of the armature for varying the resistance in said circuit in a direction contrary'to variations in the field regulating resistor.

JOSEPH F. KOVALSKY. LAWRENCE L. FOUNTAIN. 

